Live Data
Kp Index Today
Live Geomagnetic Activity
The Kp index measures global geomagnetic activity on a 0–9 scale. Check today's live reading from NOAA — and what it may mean for your mood, sleep, and energy.
The Activity Index above includes today's Kp index (25% weight) alongside Schumann Resonance and solar data.
Understanding the Scale
What Is the Kp Index?
The Kp index (Planetary K-index) is the global standard for measuring geomagnetic activity. It is derived from magnetometer readings at 13 observatories distributed around the world and published by NOAA's Space Weather Prediction Center every 3 hours.
The scale runs from 0 (extremely quiet) to 9 (extreme geomagnetic storm). Values of 5 or above indicate a geomagnetic storm — classified as G1 through G5 on NOAA's space weather scale.
Unlike the Schumann Resonance, which is driven primarily by lightning activity, the Kp index reflects disturbances in Earth's magnetosphere caused by solar wind and coronal mass ejections from the Sun.
Extremely calm geomagnetic conditions. Ideal for sensitive individuals.
Minor fluctuations. Most people notice nothing.
Elevated activity. Sensitive individuals may notice subtle effects.
Minor geomagnetic storm. Aurora possible at high latitudes.
Moderate storm. Power grid fluctuations possible. Aurora at mid-latitudes.
Strong to extreme storm. Potential impacts on infrastructure, satellites, and GPS.
Can you see the northern lights tonight?
Unlikely tonight — unless you are near the auroral zone
The Kp index is currently 3, indicating quiet-to-unsettled geomagnetic conditions. The aurora stays confined to its usual oval: Alaska, northern Canada, Iceland, and northern Scandinavia. For mid-latitude visibility, watch for Kp to reach 5 or higher.
See tonight's outlook for your stateAurora Forecast
Kp Index and Aurora: Where Can You See Northern Lights?
The Kp index directly determines how far south the aurora is visible. According to NOAA's Space Weather Prediction Center, higher Kp values push the auroral oval toward the equator, making northern lights visible at lower latitudes.
Aurora visibility depends on geomagnetic latitude, which differs from geographic latitude by up to 15 degrees depending on your location. Cities closer to the magnetic north pole see aurora at lower Kp values than their geographic latitude would suggest.
Solar Cycle 25 reached its predicted maximum around mid-2025 according to NOAA, making 2025–2026 a prime period for aurora activity. The cycle has been tracking near or above predictions, increasing the frequency of Kp 5+ geomagnetic storm events.
Aurora Visibility by Kp Level
NOAA Space Weather Prediction Center — G-scale data
Northern Montana, Minnesota, Michigan, Maine
New York, Idaho, northern tier states
Illinois, Oregon, Chicago, Boston
Alabama, northern California
Florida, southern Texas
Best Viewing Conditions
How to Read an Aurora Forecast
Check the current Kp index (above). Kp 5+ means aurora can reach the northern-tier US states; below Kp 4, it stays near the Arctic.
Compare Kp to your latitude using the table on this page. Your geomagnetic latitude — not geographic — decides your threshold.
Check darkness and weather. Aurora needs a dark sky (10 PM – 2 AM is best) and clear conditions; a full moon or city lights wash it out.
Watch the trend, not just the number. Kp is a 3-hour global index — a rising trend after a CME arrival matters more than a single reading.
Get a Heads-Up When Aurora Odds Rise
Because aurora visibility is driven by the Kp index, a Kp storm alert is effectively an aurora heads-up. The ResonanceOne app sends free push notifications when the Kp index reaches geomagnetic storm levels — the same threshold (Kp 5+) at which northern lights become possible at mid-latitudes.
ResonanceOne is not a dedicated aurora app — there is no aurora map or location-based visibility forecast. What you get is the underlying signal: live Kp, solar flare activity, and Schumann Resonance in one calm Activity Index, with alerts when any of them spike. Pair it with this page's visibility table and you know when to step outside and look north.
Get Free Kp Storm AlertsMethodology
How Kp Fits Into the Activity Index
Schumann Resonance
Real-time frequency and amplitude data from Tomsk Observatory — the primary signal driving the Activity Index.
Kp Index
NOAA's planetary geomagnetic index updated every 3 hours. The Kp component reflects geomagnetic storm intensity.
Solar Activity
Solar flare classification and X-ray flux from NOAA's GOES satellite network.
Research & Wellbeing
Kp Index and Human Health: What Research Shows
Research is ongoing. These are findings from peer-reviewed literature — not medical claims. Content last reviewed: .
Heart Rate Variability (HRV)
Multiple peer-reviewed studies have found correlations between elevated Kp index and reduced heart rate variability — a marker of autonomic nervous system balance. A 2018 study in Scientific Reports found significant HRV changes during elevated geomagnetic periods across long-term participant data.
Sleep Quality and Melatonin
Research by Burch et al. (2000) found reduced nocturnal melatonin levels during periods of elevated geomagnetic activity. Melatonin regulates the sleep-wake cycle, and disruption in its production has been associated with sleep onset difficulty and lighter sleep stages.
Mood and Emotional State
Population-level studies have found correlations between periods of high geomagnetic activity and increased reports of anxiety, irritability, and mood instability. A 2018 Frontiers in Physiology study found associations between solar/geomagnetic activity and emotional coherence measures.
Blood Pressure
A 2025 observational study in Nature Scientific Reports found statistically significant associations between elevated Kp index and measurable blood pressure changes. People with existing cardiovascular conditions may show stronger responses.
Individual variation is large. Not everyone experiences effects during high Kp periods. Correlation does not imply causation. ResonanceOne does not make medical claims.
Know the Difference
Kp Index vs. Schumann Resonance
They are often confused online. They measure completely different things.
Common Questions
Kp Index FAQ
What is the Kp index?
The Kp index (Planetary K-index) measures global geomagnetic activity on a scale of 0–9. It is derived from magnetometer readings at 13 observatories worldwide, published by NOAA every 3 hours. Kp 0–1 is quiet; Kp 5+ indicates a geomagnetic storm.
What Kp level causes a geomagnetic storm?
A Kp of 5 or higher triggers a geomagnetic storm: G1 (Kp 5, minor), G2 (Kp 6, moderate), G3 (Kp 7, strong), G4 (Kp 8, severe), G5 (Kp 9, extreme). G3+ storms can affect power grids and make aurora visible at unusually low latitudes.
How often does the Kp index update?
NOAA publishes the Kp index every 3 hours. ResonanceOne incorporates the latest reading into the Activity Index, which updates hourly.
Can a high Kp index affect how I feel?
Peer-reviewed research has found correlations between high Kp and reduced heart rate variability, sleep disruption, and mood changes in some populations. Individual sensitivity varies widely and the mechanisms are not fully established. ResonanceOne presents data for awareness, not diagnosis.
What is the difference between the Kp index and Schumann Resonance?
They measure completely different things. Kp measures geomagnetic disturbance from solar wind. Schumann Resonance measures electromagnetic resonances at 7.83 Hz driven by lightning. Both are tracked in ResonanceOne's Activity Index.
What Kp index do I need to see the aurora?
According to NOAA, aurora becomes visible at mid-latitudes starting at Kp 5 (G1 minor storm) — visible in northern Montana, Minnesota, and Maine. At Kp 6, aurora reaches New York and Idaho. At Kp 7, Illinois and Oregon. Kp 8–9 brings aurora as far south as Alabama, northern California, and even Florida during extreme events.
When is the best time to see northern lights?
Peak viewing is between 10 PM and 2 AM local time, when geomagnetic activity is strongest. September through March offers the darkest skies. Get away from city light pollution — aurora can be visible up to 1,000 km away on the horizon. Solar Cycle 25 is near its maximum, making 2025–2026 a prime aurora season.
Can you see the northern lights tonight?
It depends on tonight's Kp index — check the live answer block above. As a rule: below Kp 4, aurora stays near the Arctic (Alaska, northern Canada, Iceland, Scandinavia). At Kp 5–6, it can reach northern-tier US states like Montana, Minnesota, Michigan, and Maine. At Kp 7+, it pushes into the mid-latitudes. You also need darkness (10 PM – 2 AM is best) and clear, dark skies.
Where can you see the northern lights tonight?
How far south the aurora reaches tonight is set by the current Kp index. At Kp 5 (G1 storm) the view line touches northern Montana, Minnesota, Michigan, and Maine; Kp 6 adds New York and Idaho; Kp 7 reaches Illinois and Oregon; Kp 8–9 can bring aurora as far south as Alabama and northern California. Check the live Kp reading on this page, then find your state's threshold in the visibility table.
What time can you see the northern lights tonight?
The most reliable window is 10 PM to 2 AM local time, centered on local midnight when the auroral oval is overhead. Aurora can appear earlier or later during strong storms, but if you can only watch for one stretch, midnight is the best bet — combined with a Kp index of 5 or higher and a dark, clear sky.
How do I read an aurora forecast?
An aurora forecast comes down to three things: the Kp index (how far south the aurora can reach), your geomagnetic latitude (your personal Kp threshold), and local conditions (darkness, clouds, light pollution). Check the live Kp, compare it to your state's threshold in the table above, then go out between 10 PM and 2 AM if the numbers line up.
How can I get aurora alerts?
Aurora visibility is driven by the Kp index, so a Kp storm alert works as an aurora heads-up. The ResonanceOne app sends free push notifications when the Kp index reaches storm level (Kp 5+) — the same threshold at which aurora becomes possible at mid-latitudes. For a dedicated aurora map with location-based probability, pair it with an aurora-specific app; ResonanceOne covers the underlying geomagnetic signal.
What does Kp stand for?
The "K" comes from the German word Kennziffer ("characteristic digit"), a scale introduced by geophysicist Julius Bartels in 1938 to grade local magnetic disturbance. The "p" stands for planetary — Kp is the planetary average of standardized K values from 13 observatories worldwide.
Is a Kp index of 5 good?
It depends on what you want. For aurora watchers, Kp 5 is good news: it marks a G1 minor geomagnetic storm, with aurora possible at northern-tier US latitudes. For satellite operators and power grids, it means minor fluctuations. For wellbeing, some studies find correlations between Kp 5+ and sleep or HRV changes in sensitive individuals, but most people notice nothing.
What is the difference between the Kp index and the G-scale?
The Kp index (0–9) measures geomagnetic activity continuously, storm or not. NOAA's G-scale (G1–G5) only labels storm severity, mapping directly onto the top of the Kp scale: G1 = Kp 5, G2 = Kp 6, G3 = Kp 7, G4 = Kp 8, G5 = Kp 9. Any Kp below 5 has no G rating.
How is the Kp index calculated?
Thirteen geomagnetic observatories at mid-latitudes each record the maximum deviation of the local magnetic field during a 3-hour window and convert it into a local K value (0–9, quasi-logarithmic, calibrated per station). Those K values are standardized and averaged into the planetary Kp index, reported in 28 steps (0o, 0+, 1−, 1o, and so on up to 9o).
Does the Kp index affect drones?
It can. Geomagnetic storms (Kp 5+) degrade GPS accuracy, which drones depend on for position hold and return-to-home. Many pilots treat Kp 4 as a caution threshold and Kp 5+ as a reason to fly with extra care or manually. A high Kp will not knock a drone out of the sky — it mainly reduces positioning reliability, especially at high latitudes.
Track Kp Index and Schumann Resonance
together, in one app
ResonanceOne combines Kp index, Schumann Resonance, and solar activity into a single Activity Index. Log your mood and discover your personal patterns over time.
Learn More